Semiconductor chips available today include chips having a bottom surface with electrical contacts permitting connection of components within the semiconductor chip to other devices. Such semiconductor chips are widely referred to as “flip chips.” These semiconductor chips are frequently packaged on a substrate which has electrical conductors on one surface and contact points elsewhere in the semiconductor chip package, for example extending from a lower surface. Other electrical conductors orvias extend from the surface electrical conductor to the contact points. Conductor members, such as solder spheres or balls are positioned on the surface electrical conductors, and the semiconductor chip is positioned on the conductor members, electrically coupling the components within the semiconductor chip to the contact points of the semiconductor chip package. An underfill material, such as an epoxy, is applied around the perimeter of the semiconductor chip, and frequently also beneath the semiconductor chip, to enclose and isolate its electrical contacts and the conductor members. A second semiconductor chip might be mounted on top of the first semiconductor chip, for example being attached with an epoxy die attach material. The second semiconductor chip is connected by a number of electrical conductors, for example in the form of wires, to bonding pads in the substrate. The wires are connected to these wire bonding pads through small openings in the top insulation layer of the substrate. However, only a small amount of the underfill material is required, and it is extremely difficult to control the quantity applied and to limit the underfill to the desired area on the substrate. As a consequence, frequently access to the wire bonding pads on the substrate is wholly or partially blocked by the underfill material, making it impossible to attach the wires from the second semiconductor chip. This problem is particularly acute considering the small size of semiconductor chip. Frequently, the openings providing access to the wire bonding pads are within less than two millimeters of the edge of the first semiconductor chip, necessitating the accurate application of a very narrow band of the underfill material. The underfill material is generally applied from a nozzle-like source positioned adjacent one edge of the substrate. This often results in a projection or tongue of underfill material extending from the semiconductor chip to the edge of the substrate and blocking access to one or more of the wire bonding pads. A semiconductor chip package with such a defect is unusable. Further, semiconductor chip packages are frequently manufactured in a matrix array, permitting production of, for example, six semiconductor chip packages at a time. An underfill tongue might extend so far as to contact an adjacent semiconductor chip package, making that package unusable also.
A further shortcoming is that the semiconductor chip package is undesirably thick, particularly when it includes two semiconductor chips. This is especially disadvantageous in semiconductor chip packages for use in small consumer electronic products such as cell phones and other hand held wireless devices.